Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 16.42 kDa 
• Atom Count: 1270 
• Modelled Residue Count: 149 
• Deposited Residue Count: 153 
• Unique protein chains: 1

1X91

Crystal structure of mutant form A of a pectin methylesterase inhibitor from Arabidopsis

• DOI: 10.2210/pdb1X91/pdb

• Classification: PROTEIN BINDING
• Organism(s): Arabidopsis thaliana
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2004-08-19 Released: 2004-12-28 
• Deposition Author(s): Hothorn, M., Wolf, S., Aloy, P., Greiner, S., Scheffzek, K.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.50 Å
• R-Value Free: 0.207 
• R-Value Work: 0.184 
• R-Value Observed: 0.185 

Literature

Structural insights into the target specificity of plant invertase and pectin methylesterase inhibitory proteins

Hothorn, M., Wolf, S., Aloy, P., Greiner, S., Scheffzek, K.

(2004) Plant Cell 16: 3437-3447

• PubMed: 15528298 
• DOI: 10.1105/tpc.104.025684
• Primary Citation of Related Structures:  
  1X91, 1X90, 1X8Z


• PubMed Abstract: 
  

Pectin methylesterase (PME) and invertase are key enzymes in plant carbohydrate metabolism. Inhibitors of both enzymes constitute a sequence family of extracellular proteins. Members of this family are selectively targeted toward either PME or invertase. In a comparative structural approach we have studied how this target specificity is implemented on homologous sequences. By extending crystallographic work on the invertase inhibitor Nt-CIF to a pectin methylesterase inhibitor (PMEI) from Arabidopsis thaliana, we show an alpha-helical hairpin motif to be an independent and mobile structural entity in PMEI. Removal of this hairpin fully inactivates the inhibitor. A chimera composed of the alpha-hairpin of PMEI and the four-helix bundle of Nt-CIF is still active against PME. By contrast, combining the corresponding segment of Nt-CIF with the four-helix bundle of PMEI renders the protein inactive toward either PME or invertase. Our experiments provide insight in how these homologous inhibitors can make differential use of similar structural modules to achieve distinct functions. Integrating our results with previous findings, we present a model for the PME-PMEI complex with important implications.

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Organizational Affiliation: 

European Molecular Biology Laboratory, Structural and Computational Biology Programme, 69117 Heidelberg, Germany.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
invertase/pectin methylesterase inhibitor family protein	A	153	Arabidopsis thaliana	Mutation(s): 1  Gene Names: At1g48020, PMEI1, F21D18.29, F21D18_23, T2J15.7
UniProt
Find proteins for Q9LNF2 (Arabidopsis thaliana) Explore Q9LNF2  Go to UniProtKB:  Q9LNF2

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.50 Å
• R-Value Free: 0.207 
• R-Value Work: 0.184 
• R-Value Observed: 0.185 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 108.399	α = 90
b = 62.44	β = 94.05
c = 23.338	γ = 90

Software Package:

Software Name	Purpose
XDS	data scaling
XDS	data reduction
CNS	refinement
REFMAC	refinement
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-08-19 
• Released Date: 2004-12-28 
Deposition Author(s): Hothorn, M., Wolf, S., Aloy, P., Greiner, S., Scheffzek, K.

Revision History  

• Version 1.0: 2004-12-28
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance